Just wondering what the best plug in tuner is for my 02 2500 with a 6 liter. Mostly stock, flowmaster cat back and a k&n intake which is currently not on the truck (noticed a decrease in fuel mileage). Truck is soon to be my daily driver and I'm mainly looking for fuel mileage over power. Pulls a single car trailer with either my race car or a derby car on weekends.

I've got a Westers retune on mine . I got the 91/93 hot tune so it prefers premium but they also have a dual 87/93 tune and also changes up the trans shifting modes which I really love . The good thing is that you can request the tune to be changed if you modify the engine or want to detune it later on for whatever reason at no charge other than shipping. I got mine through Butch who is in Mass. and a very knowledgeable and super nice guy . They're not really cheap but I think are the best tune out there since they are strictly GM only . you would not have to take your computer out until the other one is in .Another good tuner is out of San Antonio called Nelson Tune but I have not used him personally . Beware the affordable tunes . They can do more harm than good . Info for Westers . Hope this helps .westersales.com/Westers/index.htm